Micro device transfer apparatus and method

ABSTRACT

A micro device transfer apparatus and a micro device transfer method are provided. The micro device transfer apparatus comprises a stage unit including a stage where a target substrate is to be disposed, a plurality of transfer head units disposed above the stage, and a transfer head unit moving part configured to move the plurality of transfer head units, wherein, the transfer head unit comprises a carrier substrate fastening part configured to fasten a carrier substrate where a plurality of micro devices are disposed, a mask unit disposed above the carrier substrate fastening part, the mask unit comprising a mask including an opening part and a shielding part, a light emitting part disposed on the mask unit, and a housing formed around the carrier substrate fastening part, the mask unit, and the light emitting part.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional application of U.S. patent applicationSer. No. 16/909,956 filed on Jun. 23, 2020, which claims priority under35 USC § 119 to Korean Patent Application No. 10-2019-0088306 filed onJul. 22, 2019, in the Korean Intellectual Property Office, thedisclosures of which are incorporated herein in their entirety byreference.

BACKGROUND 1. Field of the Disclosure

The present disclosure relates to a micro device transfer apparatus andmethod. Particularly, the present disclosure relates to a micro devicetransfer apparatus and method capable of transferring a plurality ofmicro devices from a carrier substrate to a target substrate.

2. Description of the Related Art

With the advancement of the information age, a demand for a displaydevice for displaying an image has been increased in various forms. Forexample, such a display device is applied to various electronic devicessuch as a smartphone, a digital camera, a notebook computer, anavigation device, and a smart television. Recently, as the demand forlarge-size display devices increases, substrates and backlight unitsincrease in size. Accordingly, research has been actively conducted on amicro device transfer apparatus and method that have excellent transferefficiency when a plurality of micro devices are transferred to alarge-scale substrate.

SUMMARY

Aspects of the present disclosure provide a micro device transferapparatus capable of selectively and/or quickly transferring a pluralityof micro devices from a carrier substrate to a target substrate.

Aspects of the present disclosure also provide a micro device transfermethod capable of efficiently transferring a plurality of micro devicesdisposed on a carrier substrate onto a target substrate.

It should be noted that objects of the present disclosure are notlimited to the above-described objects, and other objects of the presentdisclosure will be apparent to those skilled in the art from thefollowing descriptions.

According to an example embodiment of the disclosure, a micro devicetransfer apparatus, includes a stage unit including a stage where atarget substrate is to be disposed, a plurality of transfer head unitsdisposed above the stage, and a transfer head unit moving partconfigured to move the transfer head unit, wherein, the plurality oftransfer head units includes a carrier substrate fastening partconfigured to fasten a carrier substrate where a plurality of microdevices are disposed, a mask unit disposed above the carrier substratefastening part, the mask unit including a mask including an opening partand a shielding part, a light emitting part disposed on the mask unit,and a housing formed around the carrier substrate fastening part, themask unit, and the light emitting part.

In an example embodiment, the opening part of the mask unit exposes someof the plurality of micro devices disposed on the carrier substratefastened to the carrier substrate fastening part, and the shielding partof the mask unit shields a rest of the plurality of micro devices exceptfor the micro devices exposed by the opening part.

In an example embodiment, the light emitting part emits active light tothe carrier substrate through the mask unit.

In an example embodiment, the micro device transfer apparatus, furtherincludes a gantry frame which is disposed above the stage and on whichthe transfer head unit is mounted.

In an example embodiment, the micro device transfer apparatus, furtherincludes a transfer head unit moving module configured to move thetransfer head unit along the gantry frame as a first moving moduleinstalled on the gantry frame.

In an example embodiment, the micro device transfer apparatus, furtherincludes a support disposed outside the stage and configured to supportthe gantry frame, wherein, the support includes a vertical support partextending in a third direction, and a horizontal support part connectedto the vertical support part and extending in a second direction,wherein the gantry frame is movably connected to the horizontal supportpart, the gantry frame extends in a first direction, and the horizontalsupport part extends in the second direction intersecting the firstdirection.

In an embodiment, the micro device transfer apparatus, further includinga gantry frame moving module configured to move the gantry frame in thesecond direction.

In an example embodiment, the transfer head unit comprises a firsttransfer head unit and a second transfer head unit which are spacedapart from each other on the gantry frame.

In an example embodiment, the plurality of transfer head units furthercomprises a third transfer head unit and a fourth transfer head unit,the gantry frame comprises a first gantry frame and a second gantryframe which are spaced apart from each other, the first gantry frame isa gantry frame on which the first transfer head unit and the secondtransfer head unit are mounted, and the third transfer head unit and thefourth transfer head unit are spaced apart from each other on the secondgantry frame.

In an example embodiment, each of the plurality of transfer head unitshas a smaller planar area than the planar area of the stage.

According to an example embodiment of the disclosure, a micro devicetransfer method, includes preparing a micro device/carrier substratelaminate including a plurality of micro devices attached onto a carriersubstrate, and a first separation step of placing a mask including anopening part and a shielding part at a first location on the microdevice/carrier substrate laminate and emitting first active light toseparate some of the micro devices to which the active light is emittedthrough the opening part from the carrier substrate.

In an example embodiment, the micro device transfer method, furtherincludes attaching the micro devices separated through the firstseparation step to a first region of a target substrate.

In an example embodiment, the micro device transfer method, furtherincludes after the first separation step, a second separation step ofplacing the mask at a second location different from the first locationand emitting, second active light to separate some of the micro devicesto which the active light is emitted through the opening part from thecarrier substrate.

In an example embodiment, the micro device transfer method, furtherincludes attaching the micro devices separated through the second stepoperation to a second region different from the first region of thetarget substrate.

In an example embodiment, the micro device/carrier substrate laminatefurther comprises an adhesive film disposed between the carriersubstrate and the plurality of micro devices, and the adhesive film hasadhesion weakened by the first active light.

In an example embodiment, the micro device transfer method, furtherincludes before the first separation step, fastening the microdevice/carrier substrate laminate to a carrier substrate fastening partof a transfer head unit.

In an example embodiment, the transfer head unit comprises a firsttransfer head unit and a second transfer head unit.

In an example embodiment, the transfer head unit is mounted on a gantryframe.

In an example embodiment, after the first separation step, the transferhead unit is moved from a first region of a target substrate on whichthe first separation step is performed to a second region different fromthe first region along the gantry frame.

According to an embodiment, by transferring a plurality of micro devicesonto a target substrate using a micro device transfer apparatusincluding a plurality of transfer head units, it is possible to shortenwork time. Also, by a plurality of transfer head units transferring aplurality of micro devices onto a plurality of regions of a targetsubstrate, it is possible to efficiently transfer micro devices onto alarge-scale target substrate.

The present disclosure is not limited to the above-describedadvantageous effects, and other various effects are included in thisspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present disclosure willbecome more apparent by describing in detail example embodiments thereofwith reference to the attached drawings, in which:

FIG. 1 is a perspective view of a micro device transfer apparatusaccording to an embodiment;

FIG. 2 is a top plan view of a micro device transfer apparatus accordingto an embodiment;

FIG. 3 is a front view of a micro device transfer apparatus according toan embodiment;

FIG. 4 is a schematic front view of a carrier substrate magazine of FIG.1 ;

FIG. 5 is a bottom view of a carrier substrate magazine of FIG. 4 ;

FIG. 6 is a sectional view of a transfer head unit according to anembodiment;

FIG. 7 is a flowchart showing a micro device transfer method accordingto an embodiment;

FIG. 8 is a flowchart showing example detailed processes of a step S20and a step S30 of FIG. 7 ;

FIG. 9 is a top plan view showing a micro device transfer apparatus anda target substrate;

FIG. 10 is a layout diagram showing an example of relative placement ofa plurality of transfer head units and a target substrate in S310 ofFIG. 8 ;

FIG. 11 is a sectional view showing examples of a transfer head unit anda micro device/carrier substrate laminate in step of S320 of FIG. 8 ;

FIG. 12 is a layout diagram showing relative placement of a mask and amicro device/carrier substrate laminate of FIG. 11 ;

FIG. 13 is a layout diagram showing an example of relative placement ofa plurality of transfer head units and a target substrate in step ofS380 of FIG. 8 ;

FIGS. 14, 15, 16, 17, 18, and 19 are schematic diagrams showing a microdevice transfer method;

FIG. 20 is a top plan view of a micro device transfer apparatusaccording to another embodiment;

FIG. 21 is a layout diagram showing relative placement of a plurality oftransfer head units and a target substrate of FIG. 20 ;

FIG. 22 is a top plan view of a micro device transfer apparatusaccording to another embodiment;

FIG. 23 is a layout diagram showing relative placement of a plurality oftransfer head units and a target substrate of FIG. 22 ; and

FIG. 24 is a sectional view of a transfer head unit according to anotherembodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This disclosure may, however, be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

It will also be understood that when a layer is referred to as being“on” another layer or substrate, it can be directly on the other layeror substrate, or intervening layers may also be present. The samereference numbers indicate the same components throughout thespecification.

In concluding the detailed description, those skilled in the art willappreciate that many variations and modifications can be made to thepreferred embodiments without substantially departing from theprinciples of the present disclosure. Therefore, the disclosed preferredembodiments of the present disclosure are used in a generic anddescriptive sense only and not for purposes of limitation.

Hereinafter, example embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is a perspective view of a micro device transfer apparatusaccording to an embodiment. FIG. 2 is a top plan view of the microdevice transfer apparatus according to an embodiment. FIG. 3 is a frontview of the micro device transfer apparatus according to an embodiment.

In the drawings, a first direction D1, a second direction D2, and athird direction D3 are defined. The first direction D1 and the seconddirection D2 are horizontal, coplanar, and orthogonal to each other, andthe third direction D3 is vertical to the first direction D1 and thesecond direction D2, respectively.

Referring to FIGS. 1, 2, and 3 , a micro device transfer apparatus 1000according to an embodiment may include a stage unit 100, a plurality oftransfer head units HD1, HD2, HD3, and HD4 spaced apart above the stageunit 100 (in the third direction D3), supports 310 and 320, and gantryframes 410 and 420. The micro device transfer apparatus 1000 may furtherinclude gantry frame moving modules 331, 332, 341, and 342 and atransfer head unit moving part.

The stage unit 100 may include a base frame 110, a stage 120 disposed onthe base frame 110, and a stage moving part 130.

The stage 120 provides a space where a target substrate SUB is to bedisposed. The target substrate SUB may be seated above the stage 120 (inthe third direction D3) for the purpose of a micro device transferprocess. A substrate aligner (not shown here) may be further installedabove the stage 120 to align the target substrate SUB.

The overall planar shape of the stage 120 may follow the planar shape ofthe target substrate SUB. For example, the overall shape of the stage120 may be rectangular when the target substrate SUB is rectangular andmay be circular when the target substrate SUB is circular. In thesedrawings, the stage 120 is illustrated as having a rectangular shapewith long sides disposed in the second direction D2 and short sidesdisposed in the first direction D1.

The stage moving part 130 serves to supply the target substrate SUB tothe micro device transfer apparatus 1000 or to discharge the targetsubstrate SUB in which a plurality of micro devices are disposed. Thestage 120 may be fastened by the stage moving part 130. The stage movingpart 130 may be installed on the base frame 110, and the stage 120 maybe moved by the stage moving part 130. For example, the stage movingpart 130 may move the stage 120 in the second direction D2.

The supports 310 and 320 may include a first support 310 disposed on afirst long side of the stage unit 100 and a second support 320 disposedon a second long side of the stage unit 100 opposite to the first longside. Accordingly, the first support 310 and the second support 320 maybe spaced apart from each other in the first direction D1. The stage 120may be disposed between the first support 310 and the second support320. Accordingly, the first support 310 and the second support 320 maybe externally disposed to be adjacent to the stage 120 in the firstdirection D1.

As depicted in FIG. 1 , the first support 310 may include a firsthorizontal support part 311 extending in the second direction D2 and afirst vertical support part 312 connected to both ends of the firsthorizontal support part 311 and extending in the third direction D3,which is the vertical direction. The first vertical support part 312 mayhave an end placed on the base frame 110. The cross-sectional shape ofthe first support 310 is a rectangular, but the cross-sectional shape isnot particularly limited.

The second support 320 may include a second horizontal support part 321extending in the second direction D2 and a second vertical support part322 connected to both ends of the second horizontal support part 321 andextending in the third direction D3, which is the vertical direction.The second vertical support part 322 may have an end placed on the baseframe 110. The cross-sectional shape of the second support 320 is arectangular, but the cross-sectional shape is not particularly limited.

The gantry frames 510 and 520, which will be described below, aremovably connected to the first horizontal support part 311 of the firstsupport 310 and the second horizontal support part 321 of the secondsupport 320, and the first support 310 and the second support 320 serveto support the gantry frames 510 and 520.

The gantry frames 510 and 520 are disposed above the stage 120. Thegantry frames 510 and 520 may be disposed between the first support 310and the second support 320. As described above, the gantry frames 510and 520 may be movably connected to the first horizontal support part311 of the first support 310 and the second horizontal support part 321of the second support 320.

The gantry frames 410 and 420 may include a first gantry frame 410 and asecond gantry frame 420.

The first gantry frame 410 is disposed between the first support 310 andthe second support 320. The first gantry frame 410 may be connected tothe first horizontal support part 311 of the first support 310 and thesecond horizontal support part 321 of the second support 320. The secondgantry frame 420 is disposed between the first support 310 and thesecond support 320. The second gantry frame 420 may be connected to thefirst horizontal support part 311 of the first support 310 and thesecond horizontal support part 321 of the second support 320.Accordingly, the distance from the first gantry frame 410 and the secondgantry frame 420 to the base frame 110 in the third direction D3 may beequal to the distance from the first horizontal support part 311 and thesecond support 320 to the base frame 110 in the third direction D3.

The first gantry frame 410 may have a rectangular cross-sectional shapeextending in the first direction D1. The second gantry frame 420 mayhave a rectangular cross-sectional shape extending in the firstdirection D1. Accordingly, the extending direction of the first gantryframe 410 and the second gantry frame 420 may be equal to the firstdirection D1, i.e., the short side direction of the stage unit 100. Inan example embodiment, the first gantry frame 410 and the second gantryframe 420 may be located parallel to and spaced apart from each other inthe first direction D1. The lengths of the first gantry frame 410 andthe second gantry frame 420 extending in the first direction D1 may beequal to each other.

As depicted in FIG. 2 , a plurality of transfer head units HD mayinclude a first transfer head unit HD1, a second transfer head unit HD2,a third transfer head unit HD3, and a fourth transfer head unit HD4. Theplurality of transfer head units HD1, HD2, HD3, and HD4 are disposedabove the stage 120. The plurality of transfer head units HD1, HD2, HD3,and HD4 may be mounted on the gantry frames 410 and 420. At least one ofthe transfer head units HD1, HD2, HD3, and HD4 may be mounted on thegantry frames 410 and 420.

Each transfer head unit HD serves to place a plurality of micro devices520 (see FIG. 4 ) onto the target substrate SUB. Each transfer head unitHD1, HD2, HD3, and HD4 may be spaced a predetermined distancecorresponding to the height of the vertical support parts 312 and 322 ofthe supports 310 and 320 from the stage 120.

Each transfer head unit HD1, HD2, HD3, and HD4 may be arranged in aplurality of rows along the extending direction of the gantry frames 410and 420. Each transfer head unit HD1, HD2, HD3, and HD4 may be arrangedapart from each other on the gantry frames 410 and 420. For example, thefirst transfer head unit HD1 and the second transfer head unit HD2 maybe mounted apart from each other on the first gantry frame 410. Also,the third transfer head unit HD3 and the fourth transfer head unit HD4may be mounted apart from each other on the second gantry frame 420.However, each transfer head unit HD1, HD2, HD3, and HD4 may have adifferent arrangement direction and arrangement shape depending on theextending direction of and/or the number of gantry frames 410 and 420.By the plurality of transfer head units HD1, HD2, HD3, and HD4 beingarranged apart from each other, it is possible to prevent the collisionof the transfer head units HD1, HD2, HD3, and HD4 while the micro devicetransfer apparatus 1000 is driven.

The planar shape of each transfer head unit HD1, HD2, HD3, and HD4 mayhave a square. The transfer head units HD1, HD2, HD3, and HD4 may havethe same size. However, the transfer head units HD1, HD2, HD3, and HD4may have different sizes depending on the partitioning of a transferregion LA (see FIG. 10 ) of the target substrate SUB. The planar area ofeach transfer head unit HD1, HD2, HD3, and HD4 may be smaller than theplanar area of the target substrate SUB, which will be described below.

The first gantry frame 410 and the second gantry frame 420 may be movedin the horizontal direction by a gantry frame moving module. Thehorizontal direction in which the first gantry frame 410 and the secondgantry frame 420 move may be equal to the second direction D2, which isthe long side direction of the stage unit 100. As depicted in FIG. 1 ,the gantry frame moving module may include a first gantry frame movingmodule 331, a second gantry frame moving module 332, a third gantryframe moving module 341, and a fourth gantry frame moving module 342.

The first gantry frame moving module 331 and the third gantry framemoving module 341 may be disposed at both ends of the first gantry frame410. The first gantry frame moving module 331 may be installed on thefirst horizontal support part 311 of the first support 310, and thethird gantry frame moving module 341 may be installed on the secondhorizontal support part 321 of the second support 320. The first gantryframe moving module 331 and the third gantry frame moving module 341 maybe disposed at both ends of the first gantry frame 410 to move the firstgantry frame 410 in the second direction D2.

The second gantry frame moving module 332 and the fourth gantry framemoving module 342 may be disposed at both ends of the second gantryframe 420. The second gantry frame moving module 332 may be installed onthe first horizontal support part 311 of the first support 310, and thefourth gantry frame moving module 342 may be installed on the secondhorizontal support part 321 of the second support 320. The second gantryframe moving module 332 and the fourth gantry frame moving module 342may be disposed at both ends of the second gantry frame 420 to move thesecond gantry frame 420 in the second direction D2.

The gantry frame moving modules 331, 332, 341, and 342 may allow thefirst gantry frame 410 and the second gantry frame 420 to move on thefirst horizontal support part 311 and/or the second horizontal supportpart 321 in the second direction D2. Accordingly, by moving the firstgantry frame 410 and the second gantry frame 420 in the second directionD2, it is possible to move the plurality of transfer head units HD1,HD2, HD3, and HD4 mounted on the first gantry frame 410 and the secondgantry frame 420 in the second direction D2.

The plurality of transfer head units HD1, HD2, HD3, and HD4 may be movedin the second direction D2 by a transfer head unit moving module. Thetransfer head unit moving module may include a plurality of transferhead unit moving modules. The transfer head unit moving module mayinclude a number of transfer head unit moving modules equal to thenumber of transfer head units. In an example embodiment, the transferhead unit moving module may include a first transfer head unit movingmodule 431, a second transfer head unit moving module 432, a thirdtransfer head unit moving module 441, and a fourth transfer head unitmoving module 442. The plurality of transfer head unit moving modules431, 432, 441, and 442 may be installed on the first gantry frame 410and the second gantry frame 420.

In detail, as depicted in FIG. 1 , the first transfer head unit movingmodule 431 and the second transfer head unit moving module 432 may beinstalled on the first gantry frame 410. The first transfer head unitmoving module 431 may allow the first transfer head unit HD1 to move onthe first gantry frame 410 in the first direction D1. The secondtransfer head unit moving module 432 may allow the second transfer headunit HD2 to move on the first gantry frame 410 in the first directionD1.

The third transfer head unit moving module 441 and the fourth transferhead unit moving module 442 may be installed on the second gantry frame420. The third transfer head unit moving module 441 may allow the thirdtransfer head unit HD3 to move on the second gantry frame 420 in thefirst direction D1. The fourth transfer head unit moving module 442 mayallow the fourth transfer head unit HD4 to move on the second gantryframe 420 in the first direction D1.

The plurality of transfer head units HD1, HD2, HD3, and HD4 may behorizontally or vertically moved by the gantry frame moving modules 331,332, 341, and 342 and the transfer head unit moving modules 431, 432,441, and 442 in the first direction D1 or in the second direction D2.Through the horizontal movement of the plurality of transfer head unitsHD1, HD2, HD3, and HD4, it is possible to perform a micro devicetransfer process by transferring a plurality of micro devices 520 (seeFIG. 4 ) to the entire region of the target substrate SUB by means ofthe plurality of transfer head units HD1, HD2, HD3, and HD4 which have asmaller area than the target substrate SUB.

As depicted in FIG. 3 , a vertical moving module may be furtherinstalled between each transfer head unit moving module 431, 432, 441,and 442 and a corresponding transfer head unit HD1, HD2, HD3, and HD4.The vertical moving module may include a first vertical moving part 451,a second vertical moving part 452, a third vertical moving part 461, anda fourth vertical moving part 462. The first vertical moving part 451may be installed between the first transfer head unit HD1 and the firsttransfer head unit moving module 431. The second vertical moving part452 may be installed between the second transfer head unit HD2 and thesecond transfer head unit moving module 432. The third vertical movingpart 461 may be installed between the third transfer head unit HD3 andthe third transfer head unit moving module 441. The fourth verticalmoving part 462 may be installed between the fourth transfer head unitHD4 and the fourth transfer head unit moving module 442. The verticalmoving parts 451, 452, 461, and 462 may adjust the distance between thestage 120 and each transfer head unit HD1, HD2, HD3, and HD4 by liftingthe transfer head units HD1, HD2, HD3, and HD4 in the vertical directionwith respect to the transfer head unit moving modules 431, 432, 441, and442. That is, when the target substrate SUB is disposed on the stage120, a process of seating a plurality of micro devices on the targetsubstrate SUB may be performed by allowing the transfer head units HD1,HD2, HD3, and HD4 to be disposed to be adjacent to the target substrateSUB in the third direction D3 by the vertical moving parts 451, 452,461, and 462.

The micro device transfer apparatus 1000 may further include a carriersubstrate magazine WM. This will be described in detail with referenceto FIGS. 4 and 5 .

FIG. 4 is a schematic front view of a carrier substrate magazine of FIG.1 . FIG. 5 is a bottom view of a micro device/carrier substrate laminateof FIG. 4 .

Referring to FIGS. 1, 2, 3, 4, and 5 , the carrier substrate magazine WMmay include a plurality of carrier substrate magazines WM1, WM2, WM3,and WM4. The micro device/carrier substrate laminate 500 may include acarrier substrate 510 and a plurality of micro devices 520 disposed onthe carrier substrate 510. The carrier substrate magazine may serve tostore a micro device/carrier substrate laminate 500 including aplurality of micro devices 520 to be transferred to the target substrateSUB and supply the micro device/carrier substrate laminate 500 to thetransfer head units HD1, HD2, HD3, and HD4 through a carrier substratesupply part (not shown).

Each carrier substrate magazine WM may be externally disposed to beadjacent to at least one side of the stage unit 100. In an exampleembodiment, the carrier substrate magazine WM may be externally disposedto be adjacent to both long sides of the stage unit 100. A number ofcarrier substrate magazines equal to the number of transfer head unitsHD may be disposed. In the drawings, four transfer head units HD1, HD2,HD3, and HD4 and four carrier substrate magazines WM1, WM2, WM3, and WM4are illustrated as being disposed as an example. However, variousnumbers of carrier substrate magazines may be disposed at variouslocations.

Each carrier substrate magazine WM may store a plurality of microdevice/carrier substrate laminates 500. Referring to FIG. 4 , theplurality of micro device/carrier substrate laminates 500 may be stackedon each carrier wafer magazine WM in the third direction D3. Althoughnot shown, the micro device/carrier substrate laminates 500 disposed onthe carrier substrate magazine WM may be supplied to the transfer headunits HD1, HD2, HD3, and HD4 by means of a robot, a conveyor, or thelike. When a micro device/carrier substrate laminate 500 disposed on theuppermost portion of the carrier substrate magazine WM is provided fromthe carrier substrate magazine WM to each transfer head unit HD, thenext micro device/carrier substrate laminate 500 may be moved to theuppermost portion by a driving part of the carrier substrate magazineWM.

The carrier substrate 510 where the plurality of micro devices 520 aredisposed may contain a material that is transparent to ultraviolet (UV)light. However, the plurality of micro devices 520 may be attached to alight-transmissive substrate by an adhesive agent.

The carrier substrate 510 may be a UV film. The UV film may include a UVtransparent base film and a pressure-sensitive adhesive layer formed onone surface of the base film to fasten the substrate, and thepressure-sensitive adhesive layer may be a film having adhesive strengthdecreased when the film is exposed to ultraviolet light. Accordingly,when the carrier substrate 510 includes a UV film and is exposed to UVlight, the adhesive strength of regions of the carrier substrate 510exposed to UV light may be weakened. Alternatively, the plurality ofmicro devices 520 may be attached to the carrier substrate 510 capableof transmitting ultraviolet light by an adhesive agent having adhesivestrength weakened when the carrier substrate 510 is exposed to UV light.The plurality of micro devices 520 formed on a wafer may be formed on orattached to the carrier substrate 510 through lamination or coating toform the micro device/carrier substrate laminate 500.

The plurality of micro devices 520 may be disposed on one surface of thecarrier substrate 510 (i.e., a surface facing one side in the thirddirection D3). Each micro device 520 may include a light emitting diode(LED), an LED chip, a micro LED, and the like.

Referring to FIG. 5 , the plurality of micro devices 520 may be arrangedon the carrier substrate 510 in the form of a matrix. The plurality ofmicro devices 520 may be coplanar with and spaced a predetermineddistance from each other in the first direction D1 and the seconddirection D2. The predetermined distance between two adjacent microdevices 520 will be described in detail below.

In the drawing, as an example, the planar shape of the carrier substrate510 is a square, and the arrangement direction of the plurality of microdevices 520 is identical to the extending direction of each side of thecarrier substrate 510. However, the planar shape of the carriersubstrate 510 may be a circle.

The configuration of the transfer head unit HD according to anembodiment will be described in detail below.

FIG. 6 is a sectional view of the transfer head unit according to anembodiment. The structure of a first transfer head unit HD1 according toan embodiment will be described in detail below.

Referring to FIG. 6 , the first transfer head unit HD1 may include alight emitting part 730, a mask unit 750, a carrier substrate fasteningpart 770, and a housing 710 for accommodating the components.

The housing 710 may include a first horizontal surface 711, a sidesurface 713, and a second horizontal surface 712.

The side surfaces 713 may extend in the third direction D3 from bothends of the first horizontal surface 711, and the second horizontalsurfaces 712 may extend in the horizontal direction (i.e., the firstdirection D1 or the second direction D2) from ends of both side surfaces713. In an example embodiment, the second horizontal surface 712 mayhave a central region exposed in the third direction D3 when viewed fromthe top. By the carrier substrate 510 being disposed in the centralregion of the second horizontal surface 712, the plurality of microdevices 520 disposed on the carrier substrate 510 may be exposed in thethird direction D3.

The light emitting part 730 may be disposed at an upper portion of thetransfer head unit HD. The light emitting part 730 may serve to emitactive light so that the active light may separate the plurality ofmicro devices 520 disposed on the carrier substrate 510 from the carriersubstrate 510 of the micro device/carrier substrate laminate 500.

The active light emitted by the light emitting part 730 may behigh-energy-level light. In an example embodiment, the active light maybe near-ultraviolet light, ultraviolet light, or the like. In an exampleembodiment, when the carrier substrate 510 includes a UV film, theactive light emitted by the light emitting part 730 may be UV light. Theactive light emitted by the light emitting part 730 may mostly traveldownwardly.

The light emitting part 730 may be disposed on a bottom side of thefirst horizontal surface 711 forming the upper portion of the transferhead unit HD. In the drawing, the light emitting part 730 is illustratedas being disposed on the whole bottom side of the first horizontalsurface 711. However, the light emitting part 730 may be disposed ononly a portion of the bottom side of the first horizontal surface 711 ormay be spaced a predetermined distance from the bottom side of the firsthorizontal surface 711.

The mask unit 750 may be disposed below the light emitting part 730. Themask unit 750 and the light emitting part 730 may be entirely disposedapart from each other in the third direction D3. The mask unit 750 mayinclude a mask 751 including a plurality of opening parts 751H and theother region, i.e., a shielding part, and a mask moving module 753 formoving the mask 751 in the horizontal direction.

The mask 751 may contain a light shielding material, i.e., a materialthat does not transmit UV light emitted by the light emitting part 730.Accordingly, when the active light emitted by the light emitting part730 travels to the shielding part of the mask 751, the shielding partmay cause the active light not to reach at least a partial region of thecarrier substrate 510 of the micro device/carrier substrate laminate500. That is, by including a plurality of patterned opening parts 751H,the mask 751 serves to selectively separate only some of the pluralityof micro devices 520 disposed on the carrier substrate 510 onto thetarget substrate SUB.

The plurality of opening parts 751H are disposed on the mask 751 to passthrough the mask 751. The planar shape of each opening part 751H is notlimited. For example, the planar shape of the opening part 751H may be acircle or a square. The shape and displacement of the plurality ofopening parts 751H will be described in detail below with reference toFIG. 11 .

The mask moving module 753 may be disposed on a side surface of the mask751. The mask moving module 753 may disposed on the side surface of themask 751 to move the mask 751 in the horizontal direction. Accordingly,as will be described below, the mask moving module 753 may serve toadjust the locations of the micro devices 520 to be separated from thecarrier substrate 510 relative to the opening parts 751H during eachseparation step.

The carrier substrate fastening part 770 may be disposed at a lowerportion of the transfer head unit HD. The carrier substrate fasteningpart 770 may be disposed on a top side of the second horizontal surface712. The carrier substrate fastening part 770 may fasten, in thetransfer head unit HD, one carrier substrate 510 in which a plurality ofmicro devices 520 received from a carrier substrate magazine WM aredisposed. By fastening the carrier substrate 510 to the transfer headunit HD, the carrier substrate fastening part 770 may align a relativelocation between the carrier substrate 510 and the mask 751 just throughthe movement of the mask 751.

In an example embodiment, the transfer head units HD may have the samestructure. Accordingly, the structure of the first transfer head unitHD1 may be applied to those of the second transfer head unit HD2, thethird transfer head unit HD3, and the fourth transfer head unit HD4.Accordingly, the same description of the structures of the secondtransfer head unit HD2, the third transfer head unit HD3, and the fourthtransfer head unit HD4 will be omitted.

A method of transferring the micro devices 520 using the micro devicetransfer apparatus 1000 according to the above embodiment will bedescribed below.

FIG. 7 is a flowchart showing a micro device transfer method accordingto an embodiment. FIG. 9 is a top plan view showing a micro devicetransfer apparatus and a target substrate.

Referring to FIG. 7 , the micro device transfer method according to anembodiment may include a step of preparing a target substrate SUB on astage 120 of a micro device transfer apparatus 1000 (S10), a step ofsupplying a carrier wafer to a transfer head unit HD (S20), and a stepof arranging a plurality of light sources on the target substrate (S30).

Referring to FIGS. 1, 2, 3, 7, and 9 , a target substrate SUB isprepared on the stage 120 of the micro device transfer apparatus 1000(S10).

As shown in FIG. 9 , the target substrate SUB may be disposed on thestage 120 such that a surface opposite to a first surface of the targetsubstrate SUB to which a plurality of micro devices 520 are attached issupported by the stage 120.

As described above, the micro device transfer apparatus 1000 includesthe stage 120, a plurality of transfer head units HD1, HD2, HD3, andHD4, and a plurality of carrier substrate magazines WM1, WM2, WM3, andWM4. A plurality of micro device/carrier substrate laminates 500 aredisposed in the carrier substrate magazines WM1, WM2, WM3, and WM4. Forexample, the first transfer head unit HD1 may be located to be adjacentto the first carrier substrate magazine WM1, the second transfer headunit HD2 may be located to be adjacent to the second carrier substratemagazine WM2, the third transfer head unit HD3 may be located to beadjacent to the third carrier substrate magazine WM3, and the fourthtransfer head unit HD4 may be located to be adjacent to the fourthcarrier substrate magazine WM4.

The target substrate SUB may be disposed at the center of the stage 120of the micro device transfer apparatus 1000. The target substrate SUBmay have a planar shape of a rectangle including long and short sides.The short side of the target substrate SUB may be disposed parallel tothe short side of the stage 120, and the long side of the targetsubstrate SUB may be disposed parallel to the long side of the stage120. In an example embodiment, the target substrate SUB may be alarge-scale substrate having a rectangular shape including a long sidehaving a length of about 2000 mm to 2500 mm and a short side having alength of about 1800 mm to 2200 mm.

Particularly, the transfer head units HD may be located on the stageunit 100 adjacent to the carrier substrate magazines WM1, WM2, WM3, andWM4. Accordingly, each transfer head unit HD may not at least partiallyoverlap with the target substrate SUB in the third direction D3 whenviewed from the top. Each transfer head unit HD may be located side byside each other at least.

Subsequently, one micro device/carrier substrate laminate 500 includinga plurality of micro devices 520 is supplied to each transfer head unitHD (S20).

In detail, a micro device/carrier substrate laminate 500 disposed in thecarrier substrate magazine WM is provided to the transfer head unit HDusing a robot, a conveyer belt, or the like. The first transfer headunit HD1 may receive one micro device/carrier substrate laminate 500from the first carrier substrate magazine WM1 adjacent to the firsttransfer head unit HD1, the second transfer head unit HD2 may receiveone micro device/carrier substrate laminate 500 from the second carriersubstrate magazine WM2 adjacent to the second transfer head unit HD2,the third transfer head unit HD3 may receive one micro device/carriersubstrate laminate 500 from the third carrier substrate magazine WM3adjacent to the third transfer head unit HD3, and the fourth transferhead unit HD4 may receive one micro device/carrier substrate laminate500 from the fourth carrier substrate magazine WM4 adjacent to thefourth transfer head unit HD4. A micro device/carrier substrate laminate500 disposed on an uppermost layer among a plurality of microdevice/carrier substrate laminates 500 disposed in each carriersubstrate magazine WM may be provided to a corresponding transfer headunit HD.

Each transfer head unit that has received the micro device/carriersubstrate laminate 500 may fasten the carrier substrate 510 to thecarrier substrate fastening part 770. The micro device/carrier substratelaminate 500 fastened to the carrier substrate fastening part 770 may bedisposed such that the micro device 520 is oriented downwardly and anupper surface of the carrier substrate 510 faces a lower surface of theshielding part of the mask 751.

Subsequently, at least some of the plurality of micro devices 520 areseparated from the carrier substrate 510 and transferred from the microdevice/carrier substrate laminate 500 on each transfer head unit HD tothe target substrate SUB (S30).

The step of S30 will be described in detail in conjunction with FIGS. 8,and 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19 .

FIG. 8 is a flowchart showing examples of S20 and S30 of FIG. 7 indetail. FIG. 10 is a layout diagram showing an example of relativeplacement of a plurality of transfer head units and a target substratein S310 of FIG. 8 . FIG. 11 is a sectional view showing examples of atransfer head unit and a micro device/carrier substrate laminate in S320of FIG. 8 . FIG. 12 is a layout diagram showing relative placement of amask and a micro device/carrier substrate laminate of FIG. 11 . FIG. 13is a layout diagram showing an example of relative placement of aplurality of transfer head units and a target substrate in S380 of FIG.8 . FIGS. 14, 15, 16, 17, 18, and 19 are schematic diagrams showing amicro device transfer method.

Referring to FIGS. 8, 9, and 10 , each transfer head unit HD moves to afirst transfer target region where the micro device 520 is to bedisposed (S310 in FIG. 8 ).

In detail, by driving the gantry frame moving modules 331, 332, 341, and342, and the transfer head unit moving modules 431, 432, 441, and 442,the micro device transfer apparatus 1000 may horizontally move thetransfer head units HD to a transfer target location such that thetransfer head units HD are disposed in the thickness direction withrespect to the transfer target location to be overlapped.

Referring to FIG. 10 , the target substrate SUB may include a transferregion LA to which the micro devices 520 are to be transferred and anon-transfer region DA. The transfer region LA of the target substrateSUB may be divided into a number of regions equal to the number oftransfer head units HD. As described above, the micro device transferapparatus 1000 may include four transfer head units HD1, HD2, HD3, andHD4, and the target substrate SUB may include four transfer regionswhere the transfer head units HD1, HD2, HD3, and HD4 perform transfer.The first transfer head unit HD1 may transfer a plurality of microdevices 520 to a transfer region “a” LAa, the second transfer head unitHD2 may transfer a plurality of micro devices 520 to a transfer region“b” LAb, the third transfer head unit HD3 may transfer a plurality ofmicro devices 520 to a transfer region “c” LAc, and the fourth transferhead unit HD4 may transfer a plurality of micro devices 520 to atransfer region “d” LAd. The transfer regions may have the same area,but the present disclosure is not limited.

The transfer regions of the target substrate SUB where the transferprocess of the transfer head units HD1, HD2, HD3, and HD4 is performedmay be divided in a matrix array depending on the areas of the transferhead units HD1, HD2, HD3, and HD4. Each of the transfer head units HD1,HD2, HD3, and HD4 may be moved to a first transfer target region where afirst separation operation is to be performed. The first transfer targetregion may include a plurality of first transfer target regions wherethe first separation operation is to be performed by the transfer headunits HD1, HD2, HD3, and HD4. The first transfer target region mayinclude a region “a11” LAa11, a region “b11” LAb11, a region “c11”LAc11, and a region “d11” LAd11.

For example, the first transfer head unit HD1 may move to the region“a11” LAa11 of the target substrate SUB, the second transfer head unitHD2 may move to the region “b11” LAb11 of the target substrate SUB, thethird transfer head unit HD3 may move to the region “c11” LAc11 of thetarget substrate SUB, and the fourth transfer head unit HD4 may move tothe region “d11” LAd11 of the target substrate SUB.

Hereinafter, the driving of each transfer head unit performing transferto the first transfer target region of the target substrate SUB may bereplaced with the driving of the first transfer head unit HD1. Thedriving of the second transfer head unit HD2, the third transfer headunit HD3, and the fourth transfer head unit HD4 may be the same asdescribed below.

Next, the locations of micro devices 520 separated from the carriersubstrate 510 to the first transfer target region of the targetsubstrate SUB are aligned relative to the plurality of opening parts751H of the mask 751 (S320 in FIG. 8 ).

In detail, by changing relative locations with respect to the carriersubstrate 510 fastened to the carrier substrate fastening part 770, themask moving module 753 may perform alignment such that the opening parts751H of the mask are overlapped with the micro devices 520 a disposed inthe first transfer target region in the third direction D3.

Referring to FIGS. 11 and 12 , first micro devices 520 a disposed in theregion “a11” LAa11 of the first transfer target region among theplurality of micro devices 520 disposed on the carrier substrate 510 maybe arranged in a matrix array at predetermined distances. The distancebetween the first micro devices 520 a disposed in the region “a11” LAa11of the first transfer target region may be the same as the pitchdistance between the micro devices disposed on the target substrate SUB.

The opening parts 751H may be disposed in the mask 751 to expose themicro devices 520 in the third direction D3. Accordingly, the width WHof the opening parts 751H may be greater than the width WL of the microdevices 520. However, when the plurality of micro devices 520 are to bedisposed on the target substrate SUB on a group basis, the opening parts751H may be formed to have a different width so as to expose all of theplurality of micro devices 520.

Next, each transfer head unit HD located above the target substrate SUBis lowered onto the target substrate SUB (S330 in FIG. 8 ).

In detail, by driving the vertical moving module, each transfer headunit HD may be vertically moved to be adjacent to the first transfertarget region of the target substrate SUB. The first transfer head unitHD1 may be lowered to be adjacent to the region “a11” LAa11 of thetarget substrate SUB by driving the first vertical moving part 451, thesecond transfer head unit HD2 may be lowered to be adjacent to theregion “b11” LAb11 of the target substrate SUB by driving the secondvertical moving part 452, the third transfer head unit HD3 may belowered to be adjacent to the region “c11” LAc11 of the target substrateSUB by driving the third vertical moving part 461, and the fourthtransfer head unit HD4 may be lowered to be adjacent to the region “d11”LAd11 of the target substrate SUB by driving the fourth vertical movingpart 462.

Referring to FIG. 14 , the first transfer head unit HD1 located on theregion “a11” LAa11 of the target substrate SUB may be spaced apredetermined distance from the target substrate SUB in the thirddirection D3, but may be disposed to be adjacent to the target substrateSUB. By the first transfer head unit HD1 being disposed to be adjacentto the target substrate SUB, it is possible to prevent transfer to alocation different from a transfer target location while the microdevices 520 are being separated from the carrier substrate 510 in asubsequent operation.

Next, active light is emitted by the light emitting part 730 (S340 inFIG. 8 ).

In detail, referring to FIG. 15 , active light may be emitted onto themask 751 including the opening parts 751H and the shielding part by thelight emitting part 730. Some first micro devices 520 a transferred ontothe region “a11” LAa11 may be exposed to the active light emitted fromthe light emitting part 730 by the opening parts 751H of the mask 751,and the other micro devices 520 b and 520 c may be shielded by theshielding part of the mask 751. Accordingly, the carrier substrate 510located above some first micro devices 520 a transferred to the region“a11” LAa11 may be exposed to the active light by the opening parts 751Hof the mask 751 to have weakened adhesion. Accordingly, some first microdevices 520 a disposed on the carrier substrate 510 may be separatedfrom the carrier substrate 510 and attached to the region “a11” LAa11 ofthe target substrate SUB.

Although not shown, a flexible film or a soldering portion is disposedin the regions of the target substrate SUB to which the micro devices520 are to be attached in order to fasten the micro devices 520 to thetarget substrate SUB.

Next, each transfer head unit HD is lifted up to a predetermineddistance from the target substrate SUB (S350 in FIG. 8 ).

In detail, by driving the vertical moving module, each transfer headunit HD may be vertically moved from the first transfer target region ofthe target substrate SUB. The first transfer head unit HD1 may be liftedfrom the region “a11” LAa11 of the target substrate SUB by driving thefirst vertical moving part 451, the second transfer head unit HD2 may belifted from the region “b11” LAb11 of the target substrate SUB bydriving the second vertical moving part 452, the third transfer headunit HD3 may be lifted from the region “c11” LAc11 of the targetsubstrate SUB by driving the third vertical moving part 461, and thefourth transfer head unit HD4 may be lifted from the region “d11” LAd11of the target substrate SUB by driving the fourth vertical moving part462.

Referring to FIG. 16 , the first transfer head unit HD1 located on theregion “a11” LAa11 of the target substrate SUB may be vertically liftedfrom the target substrate SUB in the third direction D3. The firsttransfer head unit HD1 may be separated from the base frame 110 bylifting up where the first head unit HD1 has been located in an initialstep, but the present disclosure is not limited.

Next, each transfer head unit HD is moved to a subsequent transfertarget region (S380 in FIG. 8 ).

In detail, the micro device transfer apparatus 1000 may move thetransfer head units HD to the subsequent transfer target region bydriving the gantry frame moving modules 331, 332, 341, and 342 and thetransfer head unit moving modules 431, 432, 441, and 442. The subsequenttransfer target region may be a second transfer target region. Bydriving the gantry frame moving modules 331, 332, 341, and 342 and thetransfer head unit moving modules 431, 432, 441, and 442, the microdevice transfer apparatus 1000 may horizontally move the transfer headunits HD such that the transfer head units HD are disposed in thethickness direction with respect to the second transfer target region tobe partially overlapped.

For example, referring to FIGS. 10, 11, 12, and 13 , the second transfertarget region may include a region “a12” LAa12, a region “b12” LAb12, aregion “c12” LAc12, and a region “d12” LAd12. For example, the firsttransfer head unit HD1 may be horizontally moved in the first directionD1 from the region “a11” LAa11 to the region “a12” LAa12 of the targetsubstrate SUB through the first transfer head unit moving module 431,the second transfer head unit HD2 may be horizontally moved in the firstdirection D1 from the region “b11” LAb11 to the region “b12” LAb12 ofthe target substrate SUB through the second transfer head unit movingmodule 432, the third transfer head unit HD3 may be horizontally movedin the first direction D1 from the region “c11” LAc11 to the region“c12” LAc12 of the target substrate SUB through the third transfer headunit moving module 441, and the fourth transfer head unit HD4 may behorizontally moved in the first direction D1 from the region “d11” LAd11to the region “d12” LAd12 of the target substrate SUB through the fourthtransfer head unit moving module 442.

Referring to FIGS. 13, 14, 15, and 16 , the first transfer head unit HD1may be disposed in the region “a12” LAa12 of the second transfer targetregion. In order to place the plurality of micro devices 520 on thetarget substrate SUB at regular intervals, the first transfer head unitHD1 may be disposed in the third direction D3 with respect to the region“a11” LAa11 in an overlapping meaner when viewed from the top. Thepresent disclosure is not limited, and the planar area of the transferhead unit HD may be greater than the area of the plurality of unittransfer regions.

In an example embodiment, the second transfer target region and thefirst transfer target region are shown as being in the same row, but maybe placed in the same column. In this case, by horizontally moving thefirst gantry frame 410 and/or the second gantry frame 420 in the seconddirection D2 through the gantry frame moving modules 331, 332, 341, and342, each transfer head unit HD may be moved from the first transfertarget region to the second transfer target region. By horizontallymoving each transfer head unit in the same direction, it is possible toprevent collision between the transfer head units during the transferprocess.

Next, the locations of second micro devices 520 b separated from thecarrier substrate 510 to the second transfer target location of thetarget substrate SUB are aligned relative to the plurality of openingparts 751H of the mask 751 (S390 in FIG. 8 ).

In detail, by changing relative locations with respect to the carriersubstrate 510 fastened to the carrier substrate fastening part 770, themask moving module 753 may perform alignment such that the opening parts751H of the mask are overlapped with the second micro devices 520 bdisposed in the second transfer target region in the third direction D3.

Referring to FIG. 18 , by driving the mask moving module 753, the mask751 may be moved in the horizontal direction to perform alignment suchthat the second micro devices 520 b and the opening parts 751H disposedin the mask 751 are placed in the third direction D3 to be overlapped.In the first separation step, the second micro devices 520 b disposed inthe region “a12” LAa12 of the second transfer target region among theplurality of micro devices 520 b and 520 c disposed in the carriersubstrate 510 may be arranged in the form of a matrix at predeterminedintervals, like the first micro devices 520 a. The interval among thesecond micro devices 520 b disposed in the region “a12” LAa12 of thesecond transfer target region may be the same as the separation distanceamong the micro devices disposed on the target substrate SUB.

By appropriately adjusting a ratio between a distance DP between twoadjacent first micro devices 520 a disposed on the target substrate SUBand a distance DL between two adjacent first micro devices 520 adisposed on the carrier substrate 510, it is possible to efficientlytransfer all of the plurality of first micro devices 520 a disposed onthe carrier substrate 510 onto the target substrate SUB.

Referring to FIG. 19 , the distance DP between the two adjacent firstmicro devices 520 a disposed on the target substrate SUB may be definedas a distance from one side surface of a micro device 520 a disposed inthe same transfer target region of the target substrate SUB to one sidesurface of another micro device 520 a adjacent to that of the microdevice 520 a. Likewise, the distance DL between the two adjacent firstmicro devices 520 a disposed on the carrier substrate 510 may be definedas a distance from one side surface of a first micro device 520 adisposed in the carrier substrate 510 to one side surface of anotherfirst micro device 520 a adjacent to that of the first micro device 520a.

By adjusting the distance DL between the two adjacent first microdevices 520 a disposed on the carrier substrate 510 to be 1/(naturalnumber) times as great as the distance DP between the two adjacent firstmicro devices 520 a disposed on the target substrate SUB, that is, byadjusting the distance DP between the two adjacent first micro devices520 a disposed on the target substrate SUB to be a natural number timesas great as the distance DL between the two adjacent first micro devices520 a disposed on the carrier substrate 510, a plurality of separationsteps may be performed on one micro device/carrier substrate laminate500 using the same mask 751.

Meanwhile, the distance between the plurality of opening parts 751Hdisposed in the mask 751 may be proportional to the distance between thefirst micro devices 520 a disposed on the target substrate SUB. Also, ina second separation step, a movement distance DM of the mask 751 beingmoved in the horizontal direction by the mask moving module 753 may bethe same as the distance DL between the two adjacent first micro devices520 a disposed on the carrier substrate 510. In the second separationstep, by adjusting the movement distance DM of the mask 751 being movedin the horizontal direction by the mask moving module 753 to be the sameas the distance DL between the two adjacent first micro devices 520 adisposed on the carrier substrate 510, it is possible to efficientlytransfer all of the plurality of micro devices 520 disposed on thecarrier substrate 510 onto the target substrate SUB.

Referring to FIG. 8 again, after each separation step after S350, themicro device transfer method may further include comparing the number ofmicro devices 520 remaining on the carrier substrate 510 and apredetermined number K of micro devices 520 disposed in each unittransfer region (S360 in FIG. 8 ).

In detail, when the number K of micro devices 520 remaining on thecarrier substrate 510 is smaller than the predetermined number K ofmicro devices 520 disposed in each unit transfer region, the existingcarrier substrate 510 that has been disposed on the transfer head unitHD may be returned, and each transfer head unit HD may receive a newmicro device/carrier substrate laminate 500 from the carrier substratemagazine WM (N of S360 in FIG. 8 ).

Also, when the number of micro devices 520 remaining on the carriersubstrate 510 is greater than or equal to the predetermined number ofmicro devices 520 disposed in each unit transfer region, the number ofmicro devices 520 transferred onto the target substrate SUB and thepredetermined number of micro devices 520 to be transferred onto thetarget substrate SUB may be compared with each other (Y of S360 in FIG.8 ).

When the number of micro devices 520 transferred onto the targetsubstrate SUB is equal to the predetermined number of micro devices 520to be transferred onto the target substrate SUB (Y of S370 in FIG. 8 ),the target substrate SUB may be moved from the stage 120 to the outsideby the stage moving part 130. When the number of micro devices 520transferred onto the target substrate SUB is not equal to thepredetermined number of micro devices 520 to be transferred onto thetarget substrate SUB (N of S370 in FIG. 8 ), each transfer head unit HDmay perform a subsequent separation operation. That is, each transferhead unit HD is moved to a subsequent transfer target location (S380 inFIG. 8 ).

FIG. 20 is a top plan view of a micro device transfer apparatusaccording to another embodiment. FIG. 21 is a layout diagram showingrelative placement of a plurality of transfer head units and a targetsubstrate of FIG. 20 .

The embodiment shown in FIGS. 20 and 21 is different from the embodimentshown in FIG. 9 in that a fifth transfer head unit HD is furtherincluded. The embodiment shown in FIGS. 20 and 21 will be described,focusing on differences from the embodiment shown in FIGS. 9 and 10 .

Referring to FIGS. 20 and 21 , a micro device transfer apparatus 1000_2may further include a third support 370, a fifth transfer head unit HD5,a fifth carrier substrate magazine WM5, and a fifth transfer head unitmoving module 390.

In detail, the third support 370 may be disposed on the base frame 110of the stage unit 100. The third support 370 may be disposed between thefirst support 310 and the second support 320. The third support 370 maybe spaced a predetermined distance apart from the first support 310 andthe second support 320. The third support 370 may be disposed at thecenter of the stage unit 100.

The third support 370 may include a third horizontal support partextending in a horizontal direction and a third vertical support partconnected to both ends of the third horizontal support part andextending in the third direction D3, which is a vertical direction. Theextending direction of the third horizontal support part may be the sameas the second direction D2, which is the long side direction of thestage unit 100. The third horizontal support part may be spaced apredetermined distance from the base frame 110 by the third verticalsupport part. The distance from the base frame 110 up to the thirdhorizontal support part may be smaller than the distance from the baseframe 110 up to the first horizontal support part 311. Accordingly, thethird horizontal support part may be disposed below the first gantryframe 410 and the second gantry frame 420.

The fifth transfer head unit HD5 may be mounted on the third support370. The fifth transfer head unit HD5 may be moved in the horizontaldirection by the fifth transfer head unit moving module 390. The fifthtransfer head unit HD5 may be moved in the extending direction of thethird support 370, that is, in the second direction D2. Unlike movementpaths of the first transfer head unit HD1, the second transfer head unitHD2, the third transfer head unit HD3, and the fourth transfer head unitHD4, the fifth transfer head unit HD5 may be moved only in the seconddirection D2 to transfer a plurality of micro devices 520 onto atransfer region “e” LAe of the target substrate SUB.

In this embodiment, the target substrate SUB may be divided into fiveregions equal to the number of transfer head units, that is, a transferregion “a” LAa, a transfer region “b” LAb, a transfer region “c” LAc, atransfer region “d” LAd, and a transfer region “e” LAe, and eachtransfer head unit HD may transfer the plurality of micro devices 520onto a corresponding transfer region. The transfer regions may havedifferent areas. The present disclosure has a technical meaning withrespect to a uniform planar area ratio between the target substrate SUBand the carrier substrate 510 or a uniform region of the targetsubstrate SUB where the micro devices 520 are disposed without collisionbetween the transfer head units.

FIG. 22 is a top plan view of a micro device transfer apparatus 1000_3according to another embodiment. FIG. 23 is a layout diagram showingrelative placement of a plurality of transfer head units and a targetsubstrate of FIG. 22 .

The embodiment shown in FIGS. 22 and 23 is different from the embodimentshown in FIG. 9 in that one transfer head unit HD is mounted on each ofgantry frames 410 and 420. The embodiment shown in FIGS. 22 and 23 willbe described, focusing on differences from the embodiment shown in FIGS.9 and 10 .

Referring to FIGS. 22 and 23 , one transfer head unit HD may be mountedon each of the gantry frames 410 and 420. Accordingly, the transferregion of the target substrate SUB may be vertically divided, and theneach transfer head unit HD may transfer a plurality of micro devices.

FIG. 24 is a sectional view of a transfer head unit according to anotherembodiment.

A transfer head unit HD1_2 of FIG. 24 is different from the transferhead unit HD1 of FIG. 6 in that the light emitting part 730 is replacedwith a pressure part. The embodiment shown in FIG. 24 will be described,focusing on differences from the embodiment shown in FIG. 6 .

Referring to FIG. 24 , a carrier substrate 510 of a micro device/carriersubstrate laminate 500 provided to the transfer head unit HD1_2 mayinclude a pressure sensitive adhesive. Accordingly, when a verticalpressure stand 795 disposed above the transfer head unit HD1_2 islowered onto a transferred first micro device 520 a to apply pressure tothe region of the carrier substrate 510 where the first micro device 520a separated to a first transfer target location is disposed, the firstmicro device 520 a may be separated from the carrier substrate 510 tothe first transfer target location.

What is claimed is:
 1. A micro device transfer method comprising:preparing a substrate including a plurality of micro devices attachedonto a carrier substrate; fastening the substrate to a carrier substratefastening part of a transfer head unit; and a first separation step ofplacing a mask unit including an opening part, a mask having a shieldingpart, and a mask moving module for moving the mask in a first directionat a first location on the substrate and emitting first active light toseparate some of the micro devices to which the active light is emittedthrough the opening part from the carrier substrate.
 2. The micro devicetransfer method of claim 1, further comprising attaching the microdevices separated through the first separation step to a first region ofa target substrate.
 3. The micro device transfer method of claim 2,further comprising, after the first separation step, a second separationstep of placing the mask unit at a second location different from thefirst location and emitting second active light to separate some of themicro devices to which the active light is emitted through the openingpart from the carrier substrate.
 4. The micro device transfer method ofclaim 3, further comprising attaching the micro devices separatedthrough the second separation step to a second region different from thefirst region of the target substrate.
 5. The micro device transfermethod of claim 1, wherein, the substrate further comprises an adhesivefilm disposed between the carrier substrate and the plurality of microdevices, and the adhesive film has adhesion weakened by the first activelight.
 6. The micro device transfer method of claim 1, wherein thetransfer head unit comprises a first transfer head unit and a secondtransfer head unit.
 7. The micro device transfer method of claim 1,wherein the transfer head unit is mounted on a gantry frame.
 8. A microdevice transfer method comprising: preparing a substrate including aplurality of micro devices attached onto a carrier substrate; a firstseparation step of placing a mask unit including an opening part, a maskhaving a shielding part, and a mask moving module for moving the mask ina first direction at a first location on the substrate and emittingfirst active light to separate some of the micro devices to which theactive light is emitted through the opening part from the carriersubstrate; and before the first separation step, fastening the substrateto a carrier substrate fastening part of a transfer head unit, whereinthe transfer head unit is mounted on a gantry frame, and wherein afterthe first separation step, the transfer head unit is moved from a firstregion of a target substrate on which the first separation step isperformed to a second region different from the first region along thegantry frame.